Sir.—In his presentation in the Journal (129:1313, 1975), Dr Schmitt reviews some patterns typically seen on the protocols of psychological tests, proposes that these patterns are ambiguous, and concludes that psychological testing is diagnostically worthless. For example, he states that
... verbal-performance discrepancies on intelligence tests have been touted as diagnostic of organicity and hence MBD. Less well known is the fact that these same abnormalities are equally characteristic of other groups of children, especially those with psychiatric disorders.
This is an oversimplification of the highly complex matter of scatter analysis. The use of scatter analysis to aid in diagnosing organicity involves a meticulous study of the subtle comparative relationships among the 12 subtests that comprise the Wechsler Verbal and Performance Scales. To neglect the intricacies of this delicate assessment and to subsume the innumerable permutations of subtest scatter under the rubric of "verbal-performance discrepancies" is to treat psychological testing